There are numerous devices and methods known in the art to deter birds from nesting or perching on various structures. Depending on the particular bird to be deterred, and especially depending on the site of installation, the configuration of such devices may vary considerably. For example, where birds need to be deterred on a relatively confined space (e.g., rim or ledge of a building), a rack of spikes may be installed.
However, such spike racks are often impractical and unsightly, especially where the area to be protected is relatively large. To protect larger areas, or to deter relatively big bids (e.g., crows, sea gulls, etc.), known bird deterrents have a center post and radially extending arms that rotate in the wind. Typically, such deterrents include a protective or functional terminal portion on the distal end of the arm to better engage with the wind, act as an additional visual deterrent, and/or to provide physical protection against unintended contact. Examples for such devices are described in U.S. Pat. No. 6,640,506 to Landers, U.S. Pat. Nos. 5,343,651 and 5,452,536 to Chatten, U.S. Pat. No. 4,074,653 to Pember, and U.S. Pat. No. 3,292,319 to McCarthy.
While the above devices prevent various birds from perching or nesting on the protected structure, various disadvantages nevertheless remain. Most notably, the protective or functional terminal portion typically increases the surface area to a significant amount, which provides for a large area of condensation and condensate run-off, especially in marine and coastal areas. Such run-off is further often laden with particulate matter and smog, leaving the areas below the bird deterrent often spotted with drip marks and other discolorations. Moreover, in all or almost all of the known bird deterrents, the protective or functional terminal portion tends to increase visibility of the device, which is not always desirable.
Therefore, while numerous methods and devices for deterring birds are known in the art, all or almost all of them suffer from one or more disadvantages. Thus, there is still a need to provide improved bird deterrent devices.